Sunday, June 7, 2015

Dining Set Tutorial #2 Rails and Angled Tenons

Angled joinery is probably the most intimidating part of chairs. Ya, these joints take a little more time and skill, but the angles are necessary for a comfortable chair. I'll explain.


If you trace the outline of how we all sit, legs forward, it's not a square - more of a trapezoid. You can try to simplify a chair with right angle joinery and a square seat. My first chair was made this way (photo below). I found that design in a magazine gave it my best shot. It was good practice, but not the most comfortable chair. 
Sorry Woodsmith, this chair design was lame. 

I suppose the chair above could be improved upon with a trapezoidal solid seat that simply overhung the front legs.

Another innovative design of straight joinery is Mark Ripley's chair design:

You see what Mr. Ripley did there? The side rails stay straight, but the chair widens in the front. A pretty cool idea. 

Somewhere along the way I stopped avoiding angled joinery and began trying different methods to get the job done. I've had success with using loose tenons and angled mortises in the past. For this dining set, I decided to make angled tenons for side rails, like this:

Years back I would've been intimidated to make a joint like that because I used to think I had to get the joint perfect with power tools. Nowadays, I'm more skilled with hand tools and I know that I can always fine tune and finesse the joint if needed.

And Build...

I recommend making a little pattern to scale for your chair rails and seat. Trouble is, when my shop elves see me draw on something, they want to draw on it too.

As I mill all the rails and joinery, I keep coming back to this pattern. Need to know how long to saw the side rails with the tenons? Back to the pattern, and so on.

This is essentially the same pattern I got from Kevin Rodel's chair in Fine Woodworking, and the dimensions still work well for this set. You can see the seat frame is trapezoidal, angled at "85.5 degrees" in the front. But lets be real- there's no 0.5 degrees in woodworking. There's only plane and chisel shavings.

When I cut my side rails to length, I cut the ends with the tablesaw blade leaned over about 4 or 5 degrees. Also, with the blade leaning at that angle, I cut kerfs for the angled shoulders on my side rails.

The kerfs for the top and bottom edge were cut with the miter sled at our approximate 4-5 degrees. With all kerfs/shoulders cut, my side rails looked like this on each end.

A 4.5 degree kerf all the way around. Leaving 1/2" tenon inside. 

Then I cut the cheeks by adding a little angled ramp to my shop-made tenoning jig. This worked...ok. If I did it again I would probably make angled sled for the bandsaw.

Alright, my side rails are all made with angled tenons. One nice thing about doing it this way is realizing that all my mortises will be straight. No drilling at angles. 

The front and rear rails for the chair frame are easier because they're just straight up mortise and tenon joinery. I've detailed my dado blade and mortising machine method in another tutorial.

Next up I'll bust out the 8/4 (2") stock for the front legs and curved back rails.

Thanks for reading, 

Dan Westfall